Control means for the control of the piston stroke of a piston pump



Nov..24, 1970 J.KUBINEK 51m. 9 3,541,892

CONTROL MEANS FOR THE CONTROL OF THE PISTON STROKE OF A PISTON PUMP Filed Jan. 31, 1969 W INVENTORS ,Jin $50706, if/05 Val-277e, /?ud0// 7024 4 Z0907 fi/fschl United States Patent US. Cl. 74-839 2 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to control means for the control of the stroke of a piston pump with a reciprocating and simultaneously rotating piston.

Piston pumps with rotating and simultaneously reciprocating pistons are known, whereby the piston strokes are controlled by stable cams. Equally well known are similar pumps with only reciprocating pistons, the piston strokes of which are controlled by rotating cams. In both cases a reduction of the amount of the pumped liquid is achieved by reducing the actual piston stroke so that the whole possible piston stroke is not utilized for pumping. Thus is reduced, according to need, the amount of the pumped liquid and also the volumetric efiiciency of the pump.

Actually known pumps of this kind have the drawback, that the wear of different elements of the pump has a notable influence on the amount of the pumped liquid. Due to the abrasive wear of mutually engaging active surfaces in the course of prolonged operation, the piston stroke is subsequently reduced so that for an otherwise constant adjustment of said control elements the pumped amount is constantly reduced.

If such a pump is for instance used for the supply of lubricating oil of a combustion engine, where the amount of supplied oil has to be adjusted by said control means in dependence on the actual load, the oil supply is reduced with increasing working hours. If the pump is not repeatedly adjusted in time, insufficient lubrication could result with premature and excessive wear of, and may in an extreme case cause the seizing of, the friction surfaces.

SUMMARY OF THE INVENTION It is an object of this invention to provide control means for the control of the stroke of piston pumps which would prevent changes of the magnitude of the stroke of the piston of similar pumps due to wear of different elements of said pump after prolonged operation.

It is another object of this invention to allow at the same time the adjustment of the amount of the supplied liquid in dependence on external conditions, for instance on the load of a combustion engine, for which lubricating oil is supplied by such a pump.

This object is achieved according to this invention by mutually compensating the wear of active and control elements of the pump so that it is possible to maintain, in the course of the whole life time of the pump and for a certain adjustment, a constant delivery of liquid even in case of substantial wear of active contact surfaces,

3,541,892 Patented Nov. 24, 1970 ice provided said surfaces are properly designed. Such a pump therefore needs no additional adjustment and the delivered amount of liquid need not be checked, as it remains constant at any adjusted conditions during the course of operation.

DESCRIPTION OF THE DRAWING An examplary embodiment of the object of this invention is shown in the accompanying drawing in a sectional elevation.

DESCRIPTION OF PREFERRED EMBODIMENT Within the proper body 14 of the pump a cylindrical insert 18 is fixed, provided with an axial bore 19. A piston 4 engages into said bore 19 and is furthermore supported by a bearing in the cover 20 of the pump body 14. The piston 4 is adapted to perform a reciprocating movement in the axial bore 19 and simultaneously a rotating movement around its longitudinal axis. A worm wheel 15, is for this purpose, fixed to the piston 4 and engages with a worm 16, which is driven by transmission means not shown on the drawing. A stable cylindrical axial cam 1 is fixed in the pump body 14, encompassing the piston 4. The active surface of the cam 1 can be for instance represented by two partial helical surfaces of opposite lead. The piston 4 is provided with an extension 3, in the embodiment shown with a bolt, adapted for engagement with the active surface of the cam 1. The helical active surfaces of said cam 1 secures a linear contact with the bolt 3 in all positions. In addition to the worm wheel 15, a shoulder 7 and a disk 8 are fixed on the piston 4, taking part both in its rotational and in its reciprocating motion. A control disk 11 is rotatably supported on the cylindrical insert 18 of the pump body 14. The control disk 11 is provided on the part facing the pump body 14 with an annular groove 10, the depth of which increases and decreases as for instance in a uniformly and equally formed helix. The axial position of the control disk 11 is secured by the disk 17 and a snap ring, and is adjusted by inserts 13 of suitable thickness. The basic angular position of the control disk 11 is maintained by a helical spring 12, the extremities of which engage both into openings of the disk 11 and the disk 17. A stop, not shown on the drawing, secures this piston in its basic angular position.

The axial position of the control disk 11 is generally adjusted by means of inserts 13 so, that if the control disk 11 is in its basic angular position, the pump delivers a minimum amount of lubricant required for idle run of the engine.

A bore 21 is provided in the pump body 14 parallel with the longitudinal axis of the piston 4. A bolt 9 is inserted in said bore 21, and is adapted to slide freely in its axial direction. One extremity of the bolt 9 rests against the disk 8, the other extremity against the bottom of the annular groove 10 of the control disk 11. The bolt 9 thus represents stop means, limiting the stroke of the piston. A helical spring 5 resting by means of a disk 6 against the shoulder 6 of the piston 4 urges the piston 4 in the axial direction, so that a contact is established either between the extension 3 and the active surface of the cam 1 or between the disk 8 and the bolt 9.

The control disk 11 is provided on its circumference with a groove, retaining, for example, a Bowden cable which can be manipulated to act against the force of the spring 12 and by means of which the angular position of the control disk 11 can be controlled. Thus by urging the bolt 9 more or less forward, and the required amount of pumped liquid is adjusted. If the pump is used in connection with a combustion engine, the Bowden cable can be linked with the carburettor control. The cylindrical insert 18, with the bore 19 represent the cylinder of the piston 4, is provided with suction and delivery channels cooperating with grooves 22 of the piston 4. These channels which open and close in dependence on the motion of the piston 4 are not visible on the drawing.

The piston 4 receives from the worm 16 by way of the worm wheel 15 a rotating motion, in the course of which the extension 3 of the piston 4 slides along the active surface of the cam 1, against which it is urged by the force of the spring 5. Thus a reciprocating motion of the piston 4 is simultaneously generated, resulting in a pumping action as in common piston pumps. The length of the stroke of the piston 4 is however limited by the stop meansin the embodiment shown by the bolt 9, which determines which part of the active surface of the cam 1 will remain in engagement with the extension 3 of the piston 4. In general, the axial position of the control disk 11 is adjusted by means of inserts 13 so, that a minimum required amount of liquid is pumped by the pump, if no force but the force of the spring 12 acts on the control disk 11. This minimum corresponds for instance to the amount of lubricating oil required for idle run of a combustion engine. The pumped amount increases, if the bolt 9 is allowed to enter more deeply into the annular groove 10 of the control disk 11 if the angular position of the control disk 11 is changed due to the pull of the Bowden cable.

In general the amount of the pumped liquid would decrease with increasing wear of the extension 3 and of the active surface of the cam 1 since the piston stroke would be reduced. But simultaneously due to wear of the extremity of the bolt 9 and of the disk 8 and possibly also of the annular groove 10 of the control disk 11, the amount of the pumped liquid increases. It is obvious to those skilled in the art, that by correct design of the contact surfaces of the respective elements compensation can be made for both these influences, so that the pump will always deliver the proper amount of liquid. This will remain during the whole life time of the pump without regard to the wear of its active elements, in the condition to which it had been originally adjusted, without any additional adjustment.

What is claimed is:

1. Control means for the control of the piston stroke of a piston pump with a reciprocating and simultaneously rotating piston comprising:

a body,

a fixed cylindrical axial cam in said body, coaxial with the rotation axis of the piston,

an extension of said piston,

said extension engaging with said fixed axial cam, a

disk fixed on said rotating piston,

adjustable stop means engaging with said disk, limiting the stroke of said piston to control the pumping capacity thereof,

spring means urging in engagement both said extension of the rotating piston with said cylindrical cam and said adjustable stop means with said disk fixed on the rotating piston respectively.

2. Control means as claimed in claim 1 said adjustable stop means comprising a slidable bolt, coaxially arranged with the axis of the piston a rotatable control disk mounted on said body, said slidable bolt resting against the rotatable control disk, said control disk having means whereby on the rotation thereof its slidable bolt is caused to slide toward or away from said disk fixed to the reciprocating and simultaneously rotating pistons for controlling the stroke of said pistons.

References Cited UNITED STATES PATENTS 1,001,872 8/1911 Mack 103-157 1,362,144 12/1920 Rooney 103-157 1,866,217 7/1932 Mayer 103157 2,406,599 8/1946 Folke 103-157 3,353,492 11/1967 Heinzelmann et al. 103157 FOREIGN PATENTS 718,314 11/ 1954 Great Britain.

HENRY F. RADUAZO, Primary Examiner US. Cl. X.R. 7422; 9213 

